Problem A. 649. (September 2015)
A. 649. A convex polyhedron has only quadrilateral faces. Show that it is possible to split every face into two triangles by drawing one of its diagonals in such a way that at each vertex of the polyhedron, an even number of triangles meet.
Proposed by: János Nagy, Budapest
(5 pont)
Deadline expired on 12 October 2015.
Statistics:
5 students sent a solution.  
5 points:  Bodnár Levente, Lajkó Kálmán. 
1 point:  1 student. 
0 point:  2 students. 
